How to get all heder values in php?

i want to get all the Referer value from header. if page navigate from one server to another and then reach client means i need all the server hostname or Referer how can i get in php. i have used apache header which return one Referer only

There is only one referer and even then it is not to be trusted.
What you get from $_SERVER[‘HTTP_REFERER’] is all there is.

is this possible to get the referer or referer value